1. Field of the Invention
The invention relates to catalytic dewaxing with a rare earth metal ion exchanged ferrierite. More particularly the invention relates to catalytically dewaxing a waxy hydrocarbonaceous feed to reduce its pour point, using a dewaxing catalyst comprising ferrierite in which one or more trivalent rare earth metals occupy at least a portion of its cation exchange positions.
2. Background of the Invention
Catalytically dewaxing waxy hydrocarbonaceous materials such as paraffinic feeds to reduce their pour point and convert the wax to more useful products, such as fuel and lubricating oil fractions, is known. Such feeds have included petroleum derived wax containing oils, heavy oil fractions and slack wax. Dewaxing catalysts comprise a catalytic metal component, a natural or synthetic, crystalline aluminosilicate or zeolite molecular sieve component and often one or more additional refractory metal oxide components. Molecular sieves which have been found useful for dewaxing petroleum oil fractions and slack wax include, for example, ferrierite (U.S. Pat. Nos. 4,343,692 and 4,795,623), mordenite (U.S. Pat. No. 3,902,988), ZSM-23 and ZSM-35 (U.S. Pat. No. 4,222,855), ZSM-5 and ZSM-11 (U.S. Pat. No. 4,347,121) and ZSM-5 (U.S. Pat. No. 4,975,177).These various catalysts have different selectivities for different products. For example, while ZSM-5 is particularly effective for dewaxing lube oil raffinates, the cracking selectivity to gaseous products is high resulting in low lube yield. There is still a need for a dewaxing catalyst and process selective towards the production of lube oil base stocks, and particularly for premium, high purity and high VI lube oils with low pour points.